title: The role of Ia molecules in the activation of T lymphocytes. I. The activation of an IL 1-dependent IL 2-producing T cell hybridoma by Con A requires an interaction, which is not H-2-restricted, with an Ia-bearing accessory cell.
abstract: A model of accessory cell-dependent lectin-mediated T cell activation was investigated by utilizing a mitogen-inducible T cell hybridoma. A continuous MHC-restricted antigen-specific T cell line was fused with the azaguanine-resistant AKR thymoma BW5147. A hybrid, RF1.16B, was identified that is minimally inducible by Con A stimulation alone but is stimulated by Con A in the presence of T cell-depleted accessory cells to produce interleukin 2. The accessory cell function can be replaced by the monokine interleukin 1. Thus the lectin is a sufficient trigger for the hybrid in the absence of MHC restriction elements. The accessory cell function from splenocytes is provided by a non-B, non-T, predominantly Ia-bearing radioresistant cell. The interaction between the RF1.16B hybrid and the accessory cell population is not H-2-restricted. Control experiments, including the use of a cloned source of accessory cells, ruled out contaminating T cells or direct lectin effects as an explanation for the lack of H-2 restriction. The finding that an Ia-bearing cell is required for activation in an MHC-nonrestricted manner is discussed, and a hypothesis is raised that Ia antigens may play a role in addition to that of being a restriction element.
mesh_terms: D000818:Animals; D003208:Concanavalin A / Q000494:pharmacology; D006183:H-2 Antigens / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006825:Hybridomas / Q000276:immunology; D007111:Immunity, Cellular; D007375:Interleukin-1; D007376:Interleukin-2 / Q000276:immunology*; D008211:Lymphocyte Cooperation; D008222:Lymphokines / Q000276:immunology*; D008297:Male; D051379:Mice; D011506:Proteins / Q000276:immunology*; D051381:Rats; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D006183:H-2 Antigens; D000949:Histocompatibility Antigens Class II; D007375:Interleukin-1; D007376:Interleukin-2; D008222:Lymphokines; D011506:Proteins; D003208:Concanavalin A